This disclosure, in a first aspect, relates to domestic plumbing systems, particularly shower systems, that employ a thermochromic fixture to provide a visual indication of water temperature, so that water can be recirculated to a tank or reservoir until it reaches a predetermined temperature, and allowed to flow out of a shower head upon reaching the predetermined temperature. The disclosure also relates, in a second aspect, to a method of conserving water in a domestic plumbing system, through the use of a thermochromic fixture in such systems. In a third aspect, the disclosure relates to a thermochromic fixture for use in the aforesaid systems and method. In a fourth aspect, the disclosure relates to a polyvinyl chloride (PVC) formulation that exhibits thermochromic properties for use in such fixtures. In a fifth aspect, the disclosure relates broadly to system and a method, as in the aforementioned aspects, that achieve recirculation of water without a thermochromic fixture.
Shower systems for mobile applications (recreation vehicles, trailers, boats, ships, and the like) typically use water from a fresh water reservoir or tank of limited capacity. Water is directed from the tank under pressure to a shower head, with a portion of the water going through a heating unit to provide hot water, and a portion bypassing the heating unit to provide cold water. The hot water and cold water are mixed in variable proportions by a mixing valve upstream from the shower head. The heating unit, in many mobile applications, is electrically or propane powered, and may be energized only shortly before the shower is used. Also, depending on the layout of the shower plumbing, there may be a considerable volume of cool water between the heating unit and the shower head. In either case, a considerable volume of water may flow through the shower head before sufficient hot water is available to provide a shower with the desired temperature. This “unheated” flow simply goes down the drain, is thus wasted. The fresh water tank therefore must be filled more often (which is often not feasible), or water consumption in the craft or vehicle must be constrained to a level that many users would find inconvenient or uncomfortable.
It would therefore be desirable to provide a mechanism whereby the “unheated” water flow can be diverted back into the fresh water tank or reservoir for re-use, with water then being directed to the shower head only when it reaches a pre-determined temperature.